Strength balancing

So I've recently started the Insanity Workout to get back in shape and work on my stamina/endurance and it's really been exposing the differences in my right and left side. Obviously my left and right side are never going to be exactly balanced strength-wise but my right abdominals always get a much better workout than the left and is noticeably leaner on that side. Also, my left leg is a little longer than the right so it always gets a better workout and is therefore significantly stronger. Any suggestions as to how I can even things out a little bit?

Also, the longer left leg means I'm more comfortable in and tend to use unorthodox stance which annoys some people at training but it doesn't bother me all that much and I never even realised it was unorthodox until I started training MMA.